v0.1.0-U (vc=8): Phase U-1 + U-2 — Rust core + rustypipe search

NewPipeExtractor (Java) → strawcore (Rust) migration begins. Phase U:
- U-1: Rust toolchain + UniFFI smoke test
- U-2: rustypipe search via uniffi suspend fun, SearchViewModel swapped

What landed:
- rust/strawcore — UniFFI-exported Rust crate using proc-macros.
  Builds for arm64-v8a + armeabi-v7a + x86 + x86_64 via cargo-ndk.
  Tokio multi-thread runtime singleton drives rustypipe's async API.
- strawApp/build.gradle.kts — cargoBuildHost + cargoBuild + uniffiBindgen
  Gradle Exec tasks chained into the Android build. Generated Kotlin
  bindings land in src/main/java/uniffi/strawcore/ (gitignored).
- SearchViewModel.kt — calls uniffi.strawcore.search(query) directly.
  NewPipeExtractor still in deps for VideoDetail/Player/Channel paths;
  those move to Rust in U-3 / U-4.
- Build chain quirks beat:
  * cargo absolute path in Exec tasks (PATH wasn't propagating)
  * uniffi-bindgen needs UNSTRIPPED host .so — separate cargoBuildHost
    builds a debug-profile host lib to read metadata from
  * rustypipe rustls-tls-webpki-roots avoids the openssl-sys
    cross-compile tarpit
  * rquickjs-sys 'bindgen' feature opted in (no prebuilt Android
    bindings ship; crafting-table has libclang 14)
- crafting-table runtime install (until Dockerfile catches up):
  rustup + 4 Android targets + cargo-ndk + NDK r27c. Persists in
  /caches/cargo + /caches/android-sdk via the volume mount.

APK size: 22MB (U-1) → 37MB (U-2). libstrawcore.so 3-5MB per ABI carries
rustypipe + reqwest + tokio + rustls + rquickjs. NewPipeExtractor still
in for now (still drives detail + player + channel + feed), so the
Java half is doubled up. U-5 removes it.

rust/strawcore/src/runtime.rs

@@ -0,0 +1,21 @@
+// Tokio runtime singleton — rustypipe is async-first, so every exported
+// function that touches the network needs to drive a runtime. Building one
+// per call is wasteful; we build one shared multi-thread runtime at first
+// use and `block_on` against it.
+
+use once_cell::sync::Lazy;
+use tokio::runtime::Runtime;
+
+static RT: Lazy<Runtime> = Lazy::new(|| {
+    tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(2) // Mobile — we don't need many. Most blocks are I/O.
+        .enable_all()
+        .thread_name("strawcore-tokio")
+        .build()
+        .expect("strawcore: failed to build tokio runtime")
+});
+
+#[allow(dead_code)]
+pub fn block_on<F: std::future::Future>(fut: F) -> F::Output {
+    RT.block_on(fut)
+}